It has been well known for quite some time to manufacture disposable drinking containers from paper products. The sidewall of the paper container is cut in an arcuate pattern, then is formed into a frusto-conical shell. A paper bottom is then bonded or mechanically attached to the sidewall shell to form a cup that will handle hot or cold beverages. In recent years paper containers such as for example cups have been supplemented by containers manufactured of plastic material. The well known steam-chested plastic container made of expanded plastic beads represents a one piece container that has been manufactured in great numbers.
To overcome certain inherent disadvantages of paper containers and one piece steam-chested plastic containers, the container industry has found it advantageous to form various sizes of containers of plastic foam sheet material. The switch to containers made of plastic sheet foam permitted exterior decorations to be printed on the foam sheet stock by means of high speed printing techniques. It is of course recognized that the older steam-chested containers had to be decorated after the containers had been formed to their final configuration.
A further advance in the art of container manufacture occurred when it was discovered that oriented foam plastic material could be used in the manufacture of containers such as cups. When an oriented foam sheet material is utilized it is no longer necessary to cut the container sidewall as an arcuate blank. The blank can be cut in rectangular form, then formed into a cylinder by affixing opposite ends of the rectangular blank one to the other. The cylinder thus formed is subjected to heat, thus causing it to shrink in controlled fashion around a properly contoured container mandrel.
The bottom of the plastic foam container is cut in the form of a disc. The material for the container bottom disc can be of foam plastic material similar to the sidewall. The bottom discs are attached to the container sidewall by bonding with an adhesive or are heat sealed to form an integral part of the container. The container bottom disc can also be positioned within the lower edge of a cylindrical cup shell, thus permitting the shell to shrink around the bottom disc. Final sealing and contouring can be attained by pressing or ironing the container bottom subsequent to attaching the sidewall thereto.
Heretofore it has been common to form container bottoms by punching them out of sheet material, then moving them from the position where severing occurred to a position where the container bottom is combined with the sidewall of the container.
The just described procedure involved several different movements generally in a horizontal plane. The translation of the container bottom to a position where it could be combined with a container sidewall became the limiting factor in increasing the speed of the overall container fabricating machinery. Several approaches such as stacking the previously severed container bottoms, then feeding them one by one to the assembly line did not provide an adequate solution to the problem.